Human prostate as well as rat ventral prostate has the function of accumulating and secreting extraordinarily high levels of citrate. The source of citrate and metabolic relationships of citrate production have not been elucidated. This program is concerned with elucidation of four carbon (oxalacetate) source required for prostate citrate production. The utilization and incorporation of aspartate is proposed as the major four carbon source. We will investigate the source of the high endogenous aspartate level found in rat ventral prostate. The conversion of aspartate to oxalacetate via aspartate aminotransferase will be established. We will determine the presence and role of prostate glutamic dehydrogenase in regenerating alpha ketoglutarate for ATT activity. A comparison of cytosol and mitochondrial AAT will be studied. From these studies we will attempt to elucidate the metabolic pathway in prostate epithelium in which exogenous aspartate can be converted to citrate. These studies will be the forerunner of investigations relating to the hormonal regulation of prostate citrate production. Citrate production is altered in prostatic cancer and hypertrophy, and such pathological states may involve related metabolic derangements. Also the culture of human prostate will depend on the definition of appropriate conditions to retain citrate productions. This program will establish needed information for such future application.